1. Field of the Invention
The present invention generally relates to a heat exchanger, and more particularly, to a fin tube heat exchanger for use in an air conditioner or the like.
2. Description of the Prior Art
FIG. 1 depicts a conventional fin tube heat exchanger.
As shown in FIG. 1, a heat exchanger 1 is provided with a plurality of fin plates 2 of aluminum spaced at regular intervals and a plurality of heat exchanger tubes 3 extending through the fin plates 2. The heat exchanger tubes 3 are securely held in openings formed in the fin plates 2 by any suitable means. Each fin plate 2 has a plurality of narrow cut-out strips extending across the direction of flow. These strips are raised from the plane in which the fin plate 2 lies for raising the heat exchanging performance.
Japanese Patent Publication No. 63-11597 discloses a configuration of such raised strips as shown in FIGS. 2a to 2c. Raised strips 5-8 or 5-58' extend in a direction perpendicular to the direction of air flow shown by arrows A and B. The raised strips 5-8 are formed on the same side of each fin plate 2 in FIG. 2b whereas the raised strips 5-8' are formed alternately on both sides of each fin plate 2 in FIG. 2c.
In the case of the raised strips 5-8 as shown in FIG. 2b, water drops tend to stay between adjacent raised strips.
On the other hand, in the case of the raised strips 5-8' as shown in FIG. 2c, water drops tend to stay substantially in the form of a bridge between adjacent raised strips 5-8'.
In either case, water drops do not drop from the fin plate 2 until they grow into a considerable size.
Japanese Patent Laid-open Application No. 48-58434 discloses another configuration of raised strips as shown in FIGS. 3a to 3c. Similar to the heat exchanger disclosed in the foregoing Publication, raised strips 9-14 or 9-14' extend in a direction perpendicular to the direction of air flow shown by arrows A and B. The raised strips 9-14 are formed on the same side of each fin plate 2 in FIG. 3b whereas the raised strips 9-14' are formed alternately on both sides of each fin plate 2 in FIG. 3c. In the same fashion as disclosed in the foregoing Publication, water drops tend to stay between adjacent raised strips 9-14 or 9-14'. In this case, however, since each fin plate 2 is provided with a draining passage 15 along the center line of a row of heat exchanger tubes 3, not as many water drops remain as compared with the strip pattern as shown in FIGS. 2a to 2c, but the heat exchanging performance is still lowered.